Self-energizing disk brake



P 1965 R. 'r. BURNETT 3,208,557

SELF-ENERGIZING DISK BRAKE Original Filed Jan. 15, 1954 z Sheets-Sheet 1l N VEN TOR.

Iii E RICHARD r. swans-r1;

ATTdR VEY.

Sept. 28, 1965 R. T. BURNETT SELF-ENERGIZING DISK BRAKE Original FiledJan. 15, 1954 INVENTOR- RICHARD r. BUR T.

ATTORNEY.

United States Patent 3,208,557 SELF-ENERGIZING DISK BRAKE Richard T.Burnett, South Bend, Ind., assignor to The Bendix Corporation, SouthBend, Ind., a corporation of Delaware Application Aug. 8, 1960, Ser. No.48,160, now Patent No. 3,096,855, dated July 9, 1963, which is adivision of application Ser. No. 403,672, Jan. 13, 1954, now Patent No.2,955,681, dated Oct. 11, 1960. Divided and this application Sept. 26,1962, Ser. No. 226,401

3 (Ilairns. (Cl. 18872) This application for patent is a division of mycopending application Serial No. 48,160 filed August 8, 1960, now US.Patent No. 3,096,855, which in turn is a division of U3. Patent No.2,955,681, filed January 13, 1954. This invention relates to disk brakesand more particularly to improvements in disk type brakes wherein thefriction-producing elements are self-energizing components of the brake.

An object of this invention is to provide a disk brake with frictionmeans which moves in a composite axial and circumferential direction incombination with actuating means which imparts an applying thrust on thefriction means and acting in the same general angular direction as theresultant composite movement of the friction means.

Another object of the invention is to provied a disk brake in which thefriction means, the actuating means and anchoring means for the frictionmeans are co-related in such a manner to effect maximum efficiency ofthe applying force exerted on the friction means by the actuating means.

A further object of the invention is to obtain an improved wheelcylinder construction which provides for the multi-directional movementof the member to be applied.

The above and other objects and features of the invention will appearmore fully hereinafter from a consideration of the followingdescription, taken in connection with accompanying drawings, wherein aplurality of embodiments of the invention are illustrated by way ofexample.

In the drawings:

FIGURE 1 is a composite view of a side elevation of the brake assemblyillustrating in segments; (a) the brake reaction plate, (b) a sectionview taken between the reaction plate and rotor viewed toward theinboard side of the brake, (c) a section between the rotor and pressureplate looking toward the inboard side of the brake, and (d) a sectionview taken between the pressure plate and backing plate looking towardthe inboard side of the brake;

FIGURE 2 is a section view taken on the line 2-2 of FIGURE 1;

FIGURE 3 is a fragmental section view taken on the line 33 of FIGURE 1and illustrating the actuating means for applying the brake; and

FIGURE 4 is a section view of the brake taken on line 4-4 of FIGURE 1.

Referring to FIGURES 1 to 4, a nonrotatable U-shaped cross sectionmember designated generally by reference numeral consists of a backingplate 12 and reaction plate 14 secured to cylindrical flange 16 by aplurality of fastening members 18; the nonrotatable backing plate 12 isin turn, secured to a suitable fixed member such as axle flange 20 by aplurality of fastening means 22.

A rotor 24, having friction pads 26 circumferentially spaced alongeither side thereof, has a splined connection 28 with a rotatable membersuch as hub 30. Located at spaced points around the circumference of thebrake are a plurality of camming devices 32 consisting of ball-rampcombinations, the ramps 34 being recessed portions in 3,208,557 PatentedSept. 28, 1965 the backing plate 12 with oppositely facing recesses inpressure plate 36. Balls 37 are adapted to ride up the ramp portions 34upon relative circumferential movement of the pressure plate 36 andbacking plate 12 thereby causing an axial thrust on the pressure plate36.

Referring to FIGURE 3, an operator-controlled hydraulic actuator 38 isoperatively connected to pressure plate 36. The hydraulic actuator 38consists of a wheel cylinder 40, a piston 42 reciprocably receivedtherein, a sleeve 44 positioned in the head of said piston 42 and athrust link 46 operatively engaging an abutment 48 on the pressure plate36. The actuator 38 is received through an opening 50 in the supportmember 12. The support 12 is dished at 52 to accommodate the actuator.

It will be noted that the axis of the wheel cylinder 40 and thedirection of movement of the thrust link 46 is inclined with respect tothe pressure plate 36, at the same angularity as ramps 34. The purposeof this inclination will become clearer later in this disclosure inconnection with the operation of the device.

In the present illustration of the invention, two diametricallyoppositely located wheel cylinders are used. The actual number of wheelcylinder actuators is a matter of design preference; the number actuallydisclosed here is only for purposes of exemplification.

The rotor 24 is provided with a plurality of openings 54 located betweenthe friction pads 26 spaced around the circumference of the rotor. Thispermits passage of air through the brake assembly, around either side ofthe rotor in the direction and general path indicated by the arrows inFIGURE 4. The backing plate 12 contains a series of openings 56 whichpermit the air to pass through the brake assembly at the inboard side ofthe brake thereby making for complete circulation of air throughout theassembly.

A plurality of return springs 58 located in the recessed portionsinterconnect the support plate 12 and pressure plate 36 for yieldablyurging the pressure plate 36 to retracted position. The brake assemblymay include a suitable shield such as dust cover 60 fastened to therotatable hub 30 by screws 62 as shown in FIGURE 4. There is sufficientclearance between the dust cover 60 and reaction plate 14 to permit thecirculation of air therebetween.

In operation, fluid pressure generated from an appropriate mastercylinder source (not shown) causes movement of the piston 42 (see FIGURE3) in a generally downward direction. This movement of the piston bringsabout axial and circumferential movement of pressure plate 36 therebyengaging pressure plate 36 with one of the sides of the rotor 24; therotor 24 having splined connection 28 with wheel hub 30 is forced toslide axially into frictional engagement with reaction plate 14. Theengagement of the pressure plate 36 with the rotor 24 causes cammingdevices 32 to exert axial thrust on the pressure plate 36, clamping therotor 24 between the pressure plate 36 and reaction plate 14. The torquereaction from the interengagement of the rotor 24, pressure plate 36,and reaction plate 14 is transmitted through the support member 12 tothe nonrotatable axle flange 20.

From a consideration of the operation of the brake unit it will be notedthat the movement of the pressure plate is a composite axial andcircumferential motion. It is important for the input force actuatingthe brake to be exerted in the same general direction as the movement ofthe member to be applied, and for this reason the wheel cylinder in thepresent invention is oriented so that the axis thereof is in the samegeneral direction as the resultant movement of the pressure plate to beapplied thereby. that is, the thrust link 46 has the same generaldirection imposed thereupon as the direction of movement of the memberwhich it is designed to actuate. This novel location of the actuatingmeans produces maximum backing for a given input force and minimumangularity of the connecting link during actuation and retraction of thepressure plate 36.

When the operator releases the pressure generated in the wheel cylinder38, return springs 58 retract the pressure plate 36, disengaging itsfrictional contact with rotor 24 and releasing frictional contact ofrotor 24 with reaction plate 14.

Rotor 24 by reason of the circumferentially spaced friction pads 26,acts as a pump driving air through the braking system, the generaldirection of which is shown in FIG- URE 4. The openings 54 in the rotorby-pass the inflowing air on either side of the rotor and cause completecirculation of air around the periphery of the brake assembly. Thepassage of air is then across and between the ramps of the cammingdevices, and through the openings 56 where the air is expelled tocomplete the circulation through the system.

Although a particular embodiment of my invention has been described, itwill be understood by those skilled in the art that the object of theinvention may be attained by use of constructions different in certainrespects from that disclosed without departing from the underlyingprinciples of the invention.

I claim:

1. In a disk brake: a rotor having friction surfaces thereon, supportmeans extending on one side of said rotor, means movable in a directiontoward and away from said rotor and in a circumferential direction forengaging said rotor to effect braking thereof, a fluid cylinder housingcarried by said support means and having a bore whose axis is at aninclination with the plane of said rotor friction surfaces, at fluidactuated piston slidable within said bore operably connected to saidmovable means for imparting an applying thrust to said movable means,for applying the same against said rotor, the axis of said bore being inthe same general angular direction as the resultant of the compositemovement toward said rotor and circumferential movement of said pressureplate, said support means further having an anchoring abutment surfacegenerally parallel to the direction of said applying thrust and soarranged and located to receive a portion of the load exerted on saidmovable means by said rotor during brake application.

2. In a disk brake: a rotor having friction surfaces thereon, supportmeans extending on one side of said rotor, means movable in a directiontoward and away from said rotor and in a circumferential direction forengaging said rotor to effect braking thereof, a fluid cylinder housingcarried by said support means and having a bore whose axis is at aninclination with the plane of said rotor friction surfaces, a fluidactuated piston slidable within said bore operably connected to saidmovable means for applying the same against said rotor, the axis of saidbore being in the same general angular direction as the resultant of thecomposite movement toward said rotor and circumferential movement ofsaid movable means.

3. In a disk brake: a rotor having friction surfaces thereon, supportmeans located on one side of said rotor, a pressure plate located onsaid one side of said rotor and mounted for movement toward and awayfrom said rotor and in a circumferential direction, friction materiallocated between said pressure plate and said rotor, a fluid cylinderhousing carried by said support means and having a bore whose axis is atan inclination with the plane of said rotor friction surfaces, :1 fluidactuated piston slidable within said bore operably connected to saidpressure plate for imparting an applying thrust to said pressure plate,the axis of said bore being in the same general angular direction as theresultant of the composite movement toward said rotor andcircumferential movement of said pressure plate, said support meanshaving an anchoring abutment surface which is generally parallel to thedirection of thrust impaited by said actuator to said pressure plate, acamming surface on said pressure plate opposite said support meansanchoring abutment surface, a ball retained between said surfaces foreffecting camming action on said pressure plate.

References Cited by the Examiner UNITED STATES PATENTS 2,225,562 12/40Lambert 18872 2,300,532 11/42 Ash 18872 2,371,108 3/45 Oelkers 188722,373,572 4/45 Lambert 188-72 ARTHUR L. LA POINT, Primary Examiner.

EUGENE G. BOTZ, Examiner.

1. IN A DISK BRAKE: A ROTOR HAVING FRICTION SURFACES THEREON, SUPPORTMEANS EXTENDING ON ONE SIDE OF SAID ROTOR, MEANS MOVABLE IN A DIRECTIONTOWARD AND AWAY FROM SAID ROTOR AND IN A CIRCUMFERENTIAL DIRECTION FORENGAGING SAID ROTOR TO EFFECT BRAKING THEREOF, A FLUID CYLINDER HOUSINGCARRIED BY SAID SUPPORT MEANS AND HAVING A BORE WHOSE AXIS IS AT ANINCLINATION WITH THE PLANE OF SAID ROTOR FRICTION SURFACES, A FLUIDACTUATED PISTON SLIDABLE WITHIN SAID BORE OPERABLY CONNECTED TO SAIDMOVABLE MEANS FOR IMPARTING AN APPLYING THRUST TO SAID MOVABLE MEANS,FOR APPLYING THE SAME AGAINST SAID ROTOR, THE AXIS OF SAID